Resonant pulse jet fogger



June l0, 1969 V` G. L. coNGDoN 3,448,924,

` REsoNANT PULSE JET FOGGER 'i Filed Dec. 12, 196e IIIIII blz 03 PRESS United States Patent O 3,448,924 RESONANT PULSE JET FOGGER George L. Congdou, Fort Atkinson, Wis., assignor to Burgess Vibrocrafters, Inc., Grayslake, Ill., a corporation of Delaware Filed Dec. 12, 1966, Ser. No. 600,807 Int. Cl. B05b 1/24 U.S. Cl. 239-129 6 Claims ABSTRACT OF THE DISCLOSURE The lpresent invention relates to a fogger of the type wherein a resonant pulse jet engine is employed to develop the heat and fluid flow for the dispersing of a liquid material in the form of a fog. For engine fuel the present invention employs gas released from a pressurized gas bottle. The structure is such that the gas as it is released aspirates air to form a combustible mixture and forces the combustible mixture through a backflow obstructing Valve, which is so constructed as to permit the mixture flow therethrough under the pressure developed by the aspirating gas. This greatly facilitates the lability to start the engine.

Summary of the invention Foggers normally require the use of a pressurized -air source to obtain the combustible mixture in the resonant pulse jet engine during the starting procedure. See for example U.S. Patent No. 2,821,966, dated Feb. 4, 1958. Such engines often are diilcult to start because of the interrelationship of the necessity of producing a combustible mixture and then igniting that mixture. In the present invention bottled gas under pressure is employed to aspirate air to form a combustible mixture at a pressure in excess of atmospheric. This combustible mixture passes through an anti-backflow valve in a conduit leading to the combustion chamber of the engine, because of the creation of the lpressure in excess of atmospheric. So long as the engine is not running this flow will be constant. This combustible mixture is easily ignitable either in the combustion chamber of the engine or in the conduit between the valve and the combustion chamber. As compared to prior art devices employing pressurized air sources for starting, the ease of starting an engine embodying the present invention is distinctly superior.

Anti-backflow valves have previously been used in resonant pulse jet engines, see for example U.S. Patent No. 2,609,660. However, the form of the valve employed in the present invention is different from that of known prior art devices. Two spaced plates are employed with a ,thin flexible diaphragm loosely mounted between the plates. The upstream plate, as considered with respect to the flow of the combustible mixture, has holes therethrough which are adapted to be covered by the diaphragm when the pressure on the downstream side of the valve becomes greater than the pressure on the upstream side of the valve. This form of valve provides little impediment to the flow of the combustible mixture through the valve when the pressure on the downstream `side of the valve is atmospheric or below. Thus the combustible mixture may be forced `to the combustion chamber of the engine with the comparatively low pressures developed by -gas bringing in the ambient air.

Further objects and advantages of the invention will be apparent from the following description taken in conjunction with the drawings in which:

FIGURE l is an elevational sectional View, in rather schematic form, of a fogger embodying the present invention;

FIGURE 2 is an enlarged view of the aspirator and anti-backow valve, and

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FIGURE 3 is an exploded view of the valve.

Although the following disclosure offered for public dissemination is detailed to ensure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how others may later disguise it by variations in form or additions or further improvements. The claims at the end hereof are intended as the chief aid toward this purpose; as it is these that meet the requirement of pointing out the parts, improvements, or combinations in which the inventive concepts are found.

FIGURE 1 illustrates a fogger embodying a resonant pulse jet engine, generally 10, comprising a combustion chamber 11, and a resonance tube 12. A shroud 13 is employed about the combustion chamber and tube, both as a protection against burns and so that Iambient air will be aspirated about the chamber and tube by the flow of gases from the discharge end of the tube. Adjacent the discharge end of the resonance tube 12 is a venturi 14 to produce `a low pressure area to facilitate the feeding of the fogging material into the hot gaseous stream ejected from the resonance tube.

The fogging material, which for example, might be an insecticide in a kerosene carrier or vehicle, is held in a closed container 16. Container 16 has a fill opening, not shown, which may be rendered pressure tight after the fogging material is introduced into the container or tank. The fogging material flows to venturi 14 throu-gh a syphon tube -17, a control valve 18, and a pipe 19. Tank 1-6 is pressurized through pipe 20, check valve 21, and pipe 22.

A pipe 24 forms a part of a conduit for directing thel combustible mixture into the combustion chamber 11. Preferably this combustible mixture enters the combustion chamber tangentially. Located in one portion of pipe 24 is an igniter formed by a rotatable spark wheel 26, which engages a flint 27. Pipe 24 is threaded into a body section 28 having communicating openings 29 and 30 therein. A llame arrester in the form of a rod 31 with a plurality of rings or discs 32 extends along the interior of pipe 24. Rod 31 is aflixed to body section 28.

A second body section 35 is attached to body section 28 by means of fbolts 36. Body section 35 defines an enlarged chamber 37, a bell shaped housing 38, and a channel 40 communicating between the chamber 37 and the hollow interior 39 of bell 38. The cross-sectional size of channel 40 is much smaller than that of either chamber 37 or interior 39. Bell 38 has a relatively flat interior Wall 41, and denes an aspirator throat 42.

Intermediate the two body sections 28 and 35 is a gasket 44 and a first plate 45 of the anti-backflow valve. Secured to first plate 45 is a second plate 46. The two are spaced from each other by means of a washer 47, and are held in this position by a bolt 48. Loosely received in this space between the two plates is a flexible diaphragm 49. The diaphragm is substantially thinner than the space between the two plates so that it is freely movable in that space. Plate 45 has plurality of holes 50 therethrough and plate 46 has a plurality of holes 51. When the gas pressure in chamber 37 is greater than that in chamber 30, diaphragm 49 will move against plate 46 to permit the gas to flow through holes 50 in plateI 4S and from there about the sides of the diaphragm 49 into chamber 30. When the gas pressure in chamber 30 exceeds that in chamber 37, diaphragm 49 is forced into contact with plate 45 thus closing openings 50 and preventing any reverse gas flow. Diaphragm 49 is relatively thin and llexible, as for example a film of plastic impregnated fiberglass having a thickness of 0.003 inch and gas impervious. A suitableI form of impregnated fiberglass is that sold under the trademark Fluorgias No. M 381-3. Parts 44-47 and 49 all are circular.

The combustible gas is introduced through a nozzle 43, which is threaded into a cylinder 54. Cylinder 54 has external threads S5, a nut shaped end 56, and a hollow interior 57. It is threaded into and held by a mounting bar 48 affixed to housing 38. An air flow adjustment plate 59 is threaded onto cylinder 44. Plate 59 is cylindrical in external configuration. A spring 60 is in compression between plate 59 and mounting bar 58 so as to prevent any unwanted rotation of plate 59.

A pipe 63 is attached to cylinder 54 by means of a tting 64, with the pipe being in communication with the hollow interior 47 of the cylinder. Pipe 63 communicates with gas bottle 65 through control Valve 66, pipe 67, pressure regulating valve 68, and pipe 69. In actual practice these gas passages and valves may be formed in a single block. The gas in cylinder 65 may be' any combustible gas which normally is a gas at the usual ambient temperatures and atmospheric pressure, as for example propane or butane. In the usual instance it will be reduced in pressure by regulating valve 68 to about l5 to 25 pounds per square inch.

Nozzle 43 and throat 42 form an aspirator. As the gas is ejected through nozzle 53 it produces a low pressure which results in air being drawn in through bell 38 and into channel 40 to form a combustible mixture with the gas. This combustible mixture in chamber 37 is at a pressure in excess of atmospheric. It therefore pushes diaphragm 49 away from holes Si) to permit the mixture to ow through the conduit defined by opening 30, opening 29 and the hollow interior of pipe 24 to combustion charnber 11. A manual rotation of spark wheel 26 (in a clockwise direction as viewed in FIGURE l) is all that is required to ignite the combustible mixture and start the engine. The initial ignition pressurizes the combustion chamber and the conduit leading to the anti-backtlow valve. This pressure wave closes the valve for so long as the pressure in opening 30 exceeds the pressure in chamber 37. As a slug of burned gas flows down resonance tube 12 a low pressure is created in combustion chamber 11 and in the conduit leading to the anti-backflow valve. This low pressure, in conjunction with the pressure in chamber 37, results in a new charge of combustible mixture owing through the anti-backilow valve and to the combustion chamber where it is automatically ignited by the still burning gases there present. This process is repeated over and over as in the operation of a conventional resonant pulse jet engine.

TheI pressurizing of pipe 24 also results in the pressure wave owing through pipe 22, check valve 21 and pipe to pressurized container 16. This plus the low pressure existing at venturi 14 as the hot gases of combustion come out of resonance tube 12 cause the fogging material to be injected into the hot gases at venturi 14. This fogging material is ejected by the gas flow and heated thereby to produce the desired fog.

The comparatively large size of chamber 37 not onlyr permits the use of a diaphragm having a comparatively large diameter, but also provides space for the storing of a combustible mixture during those brief intervals when the anti-backtlow valve is closed by a pressure wave in opening 30. To obtain a proper combustible mixture with a given type of gas and pressure at nozzle 43, adjusting plate 59 is moved towards or away from wall 41 of bell 38. This may be done by manually rotating plate 59 one way or the' other so that it moves towards or away from wall 41.

I claim:

1. In a fogger wherein a resonant pulse jet engine with a combustion chamber is employed to develop the heat and fluid flow for the dispersing of a liquid material as a fog, the improvement comprising: a container of combustible uid under pressure, which fluid is a gas at atmospheric pressure and ambient temperature; an aspirator having a nozzle communicating with said container for introducing gas into the aspirator for flow in a given direction, said aspirator being open to atmosphere on the upstream side to permit air to be drawn therein by the aspiration effect to form a combustible mixture under a pressure in excess of atmospheric downstream of said aspirator; means forming a conduit from the downstream side of said aspirator to said combustion chamber; and Valve means in said conduit for permitting said mixture to ow therethrough to the chamber when the pressure downstream of the valve means is less than said excess pressure and for blocking the flow of fluid in the reverse direction when the pressure in the downstream side of the valve means is greater than said excess pressure; said aspirator including an externally threaded hollow cylinder having the nozzle mounted on one end in communication with the hollow interior of the cylinder, said container also communicating with the hollow interior, an air control plate about said cylinder and engaging the threads of the cylinder, and means contacting said control plate to prevent unwanted rotation of the plate on the cylinder.

2. In a fogger as set forth in claim 1, including an igniter in said conduit downstream of said valve means, said igniter comprising a int and manually operable spark wheel in contact with the int.

3. In a fogger wherein a resonant pulse jet engine with a combustion chamber is employed to develop the heat and fluid ow for the dispersing of a liquid material as a fog, the improvement compirsing: a container of combustible iluid under pressure, which uid is a gas at atmospheric pressure and ambient temperature; an aspirator having a nozzle communicating with said container for introducing gas into the aspirator for ow in a given direction, said aspirator being open to atmosphere on the upstream side to permit air to be drawn therein by the aspiration effect to form a combustible mixture under a pressure in excess of atmospheric downstream of said aspirator; means forming a conduit from the downstream side of said aspirator to said combustion chamber; and valve means in said conduit for permitting said mixture to ow therethrough to the chamber when the pressure downstream of the valve means is less than said excess pressure and for blocking the How of fluid in the reverse direction when the pressure in the downstream side of the valve means is greater than said excess pressure; said aspirator and conduit means comprising a rst body portion detachably affixed to a second body portion, said rst body portion defining an internal chamber upstream of the downstream end thereof, a hollow bell at the upstream end thereof and a uid channel communicating between the interior of the bell and the chamber, said channel being smaller in cross-section than that of the bell and chamber, said nozzle being positioned at the upstream end of the channel and directed towards said chamber; said valve means being mounted across the downstream end of said rst body portion.

4. In a fogger as set forth in claim 3, wherein said first body portion defines a transverse wall at the upstream end of the channel, said fogger including an air control plate in said bell and transversely thereto, said plate being adjustable toward and away from said transverse wall.

5. In a fogger as set forth in claim 4, wherein said aspirator includes an externally threaded hollow cylinder in the bell and axially aligned with said channel, said cylinder having the nozzle secured thereto in the channel end thereof, said nozzle and said container communicating with the hollow interior of the cylinder, said plate being about said cylinder and engaging the threads thereof, and mounting means connecting said cylinder and said bell.

6. In a fogger as set forth in claim 5, including a spring about said cylinder and in compression between said plate and said mounting means; said valve means including a rst plate extending transversely of said conduit between said two body portions, said first plate having holes therethrough, a second plate attached to the rst plate and spaced therefrom on the downstream side thereof, and a flexible diaphragm between said plates and movable in the space therebetween in a direction toward and away from 5 6 said rst plate, said diaphragm covering said holes when 2,926,855 3/1960 Drr et al 239-129 moved against said rst plate. 2,959,214 11/ 1960 Drr et al 15 8 4 3,093,962 6/1963 Gluhareff 60-39.77 X References Cited 3,279,179 10/ 1966 Kemenczky 60-247 UNITED STATES PATENTS 5 FOREIGN PATENTS 1,809,425 6/1932 Roberts 158-118 386 908 1/1933 Great Britain. 2,383,641 8/1945 Focke et al. 158-118 X 2,523,378 9/ 195 0 Kollsman- EVERETT W. KIRBY, Primary Examiner. 2,701,950 2/ 1955 Huber et al. 2,857,332 10/1958 Tenney et al 239-129 X 10 U.S. C1. X.R.

2,858,162 10/1958 Prank 239-129 252--3591 

